Lake Michigan Water Levels Heading into the Summer of 2018

The water level of Lake Michigan in June of 2018 remains above the long-term average, as it has since April of 2014. According to the U.S. Army Corps of Engineers Weekly Great Lakes Water Level Update for June 22, 2018, Lake Michigan is 18 inches above the long-term average water level for the month of June, calculated from water levels measured from 1918 to present (see the most current update here). That puts the lake 4 inches higher than this time last year. From a historic perspective, Lake Michigan is at its highest June water level since 1997 but is still 13 inches below the record high for June set in 1986.

Six-month water level forecasts from the US Army Corps of Engineers project Lake Michigan to remain above the long-term average levels in the near future (see the most current forecast here). These six-month forecasts are compiled considering estimates for future precipitation and runoff into the lake, evaporation from the lake, and outflows from the lake. In particular, the water level is expected to rise a few inches through July before beginning to drop through the fall. This pattern is to be expected, as Lake Michigan typically reaches its peak water level for the year in the summer before dropping into the fall due to seasonal changes in precipitation and evaporation.

In summary, the Lake Michigan water level is still above-average and is anticipated to be above-average for at least the rest of 2018. While high water levels themselves don’t cause shoreline erosion, high water levels allow erosive waves to reach higher elevations on the shore where they batter shoreline infrastructure and eat away at the base of bluffs and dunes. Beaches are also made smaller under high water levels, as the lake inundates portions of the beach. On the other hand, high water levels can help alleviate navigation concerns for boats and ships, providing more clearance from the bottom of harbors and channels.

Many good resources exist to learn more about Great Lakes water levels. The Army Corps of Engineers publication Living with the Lakes explains what factors influence water level changes. NOAA’s Great Lakes Water Level Dashboard is a tool to explore historic and forecasted water levels. A summary of NOAA research into the recent rise in water levels that began in 2013 is available in this article.